Metal pipes or conduits, such as, for example, Rigid Metal Conduit (RMC), Intermediate Metal Conduit (IMC), Electrical Metallic Tubing (EMT) and Rigid Aluminum Conduit (RAC), are often used to run electrical conductors over long distances, particular in corrosive or industrial atmospheres. The conduits may be buried underground or set in concrete, for example, to provide protected raceways for electrical wiring. Metal conduits for running electrical conductors are often preferred because of the protection they offer, acting as effective physical shields against a variety of environmental concerns such as water corrosion and electrical magnetic interference (EMI), while also providing the capability to serve as an effective grounding conductor.
Metal conduits are typically provided in five (5) to twenty (20) foot lengths, ten (10) foot lengths being generally preferred, and have inside diameters ranging from one half (½) inch to six (6) inches, although various other lengths and diameters may be used as well. The conduits may be formed to have bend contours for applications requiring just about any configuration of run. A primary issue for installers of these conduits is dealing with the weight of each separate conduit, a typical 10 foot conduit weighing upwards of 100 pounds. Often, when in the field, the handling required and brute force necessary to connect multiple lengths of conduit in co-axial or end-to-end relationships can be cumbersome and difficult.
Various couplings have been developed for use in joining adjacent conduits. For example, some conduits are formed with external threads at one end and a swaged section with internal threading at the other end. Joining adjacent conduits thus requires fitting the externally threaded end of a first conduit into the swaged section of a second conduit and turning either one or both of the conduits to form a structurally sound and electrically sound connection. In yet other applications, various compression couplings or other coupling assemblies have been developed. In some cases, each end of the conduit sections may be formed with external threads, and the coupling assembly may be internally threaded or use an internally threaded sleeve so that one end of each of the conduit sections may be threaded into the coupling to form a sound connection. However, particularly when one of the conduits has an elbow or other bends and/or the clearance in the area of the coupling is tight, for example, having to turn one or both of the conduits may be extremely difficult when trying to couple two adjacent conduits end-to-end.
There is a need and desire for a coupling assembly that can be easily and effectively used in the field to join two adjacent conduits end-to-end. The coupling provided must be structurally and electrically sound to guarantee the aforementioned benefits for using metal conduits when running electrical conductors.